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US4906583A
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Making a semiconductor photodetector
Assignee: Fujitsu Ltd
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Filing: 1988-08-22
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Granted: 1990-03-06
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Expires: 2008-08-22
Abstract
Abstract A semiconductor photodetector, such as a PIN photodiode and an avalanche photodiode, comprising an InP substrate, a first InP layer, a GaInAs or GaInAsP light absorbing layer, and a second InP layer. All of the layers are successively grown by a vapor phase epitaxial process wherein the lattice constant of the GaInAs (GaInAsP) layer is larger than that of the InP layer at room temperature. The photodetector has a low dark current.
Inventors
- 👤 Shuzo Kagawa
- 👤 Junji Komeno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 19:32
CPC Classifications
H; H10; H10F; H10F77/00; H10F77/10; H10F77/12; H10F77/124; H10F77/1248; H10F30/00; H10F30/20; H10F30/21; H10F30/22; H10F30/223; H10F30/225; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/544; Y10; Y10S; Y10S148/00; Y10S148/015; Y10S148/072; Y10S148/097; Y10S148/12
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
137 words
A method of forming a semiconductor photodiode comprising the steps of: preparing a InP substrate; growing a InP buffer layer on said InP substrate by a vapor phase epitaxial process using a gas including P and In; growing a Ga 1-x In x As light absorbing layer on said InP buffer layer by a vapor phase epitaxial process while controlling the flow rates of As gas, Ga gas and In gas such that the lattice mismatching degree (Δa/a) between said Ga 1-x In x As light absorbing layer and said InP buffer layer is more than 0% and less than 0.2% at room temperature, as defined by the equation: ##EQU2## gorwing a cap layer on said Ga 1-x In x As layer; and introducing impurity ions into said cap layer so as to make a Pn junctions.
Claim 2
Independent Claim
137 words
A method of forming a semiconductor photodiode comprising the steps of: preparing a InP substrate; growing a InP buffer layer on said InP substrate by a vapor phase epitaxial process using a gas including P and In; growing a Ga 1-x In x As light absorbing layer on said InP buffer layer by a vapor phase epitaxial process while controlling the flow rates of As gas, Ga gas and In gas such that the lattice mismatching degree (Δa/a) between said Ga 1-x In x As light absorbing layer and said InP buffer layer is more than 0% and less than 0.2% at room temperature, as defined by the equation: ##EQU2## gorwing a cap layer on said Ga 1-x In x As layer; and introducing impurity ions into said cap layer so as to make a Pn junctions.
Claim 3
Dependent Claim
14 words
A method according to claim 1 wherein, said "x" is between 0.531 and 0.560.
Claim 4
Dependent Claim
26 words
A method according to claim 1 wherein, said Ga 1-x ln x As light absorbing layer has a thickness of between 1 μm to 20 μm.
Claim 5
Dependent Claim
56 words
A method according to claim 1 wherein, in said step of growing the Ga 1-x ln x As light absorbing layer, As included gas is fed into a reactor in which a Ga source, In source and the InP substrate are provided, and said As included gas flows over said Ga source and In source respectively.
Claim 6
Independent Claim
151 words
A method of forming a semiconductor photodiode comprising the steps of; preparing a InP substrate; growing a InP buffer layer on said InP substrate by a vapor phase epitaxial process using a gas including P and In; growing a Ga 1-x In x As 1-y P y light a absorbing layer on said InP buffer layer by a vapor phase epitaxial process while controlling the flow rates of As gas, Ga gas, In gas, and P gas such that the lattice mismatching degree (Δa/a) between said Ga 1-x ln x As 1-y P y light absorbing layer and said InP buffer layer is more than 0% and less than 0.2% at room temperature, as defined by the equation: ##EQU3## growing a cap layer on said Ga 1-x ln x As 1-y P y light absorbing layer; and introducing impurity ions into said cap layer so as to form a PN junction.
Claim 7
Independent Claim
151 words
A method of forming a semiconductor photodiode comprising the steps of; preparing a InP substrate; growing a InP buffer layer on said InP substrate by a vapor phase epitaxial process using a gas including P and In; growing a Ga 1-x In x As 1-y P y light a absorbing layer on said InP buffer layer by a vapor phase epitaxial process while controlling the flow rates of As gas, Ga gas, In gas, and P gas such that the lattice mismatching degree (Δa/a) between said Ga 1-x ln x As 1-y P y light absorbing layer and said InP buffer layer is more than 0% and less than 0.2% at room temperature, as defined by the equation: ##EQU3## growing a cap layer on said Ga 1-x ln x As 1-y P y light absorbing layer; and introducing impurity ions into said cap layer so as to form a PN junction.
Claim 8
Dependent Claim
29 words
A method according to claim 5 wherein, said Ga 1-x In x As 1-y P y light absorbing layer has a thickness of between 1 μm to 2 μm.
Claim 9
Dependent Claim
81 words
A method according to claim 5 wherein, in said step of growing the Ga 1-x In x As 1-y P y light absorbing layer, a gas containing As and a gas containing P are fed into a reactor in which a Ga source, In source and the InP substrate are provided, said gas containing As flowing over one of said Ga source and In source, and said gas containing P flowing over the other of said Ga source and In source.
Claim 10
Dependent Claim
29 words
A method according to claim 1, further comprising a step of growing Ga 1-x In x As light absorbing layer and said cap layer, said cap layer being InP.
Claim 11
Dependent Claim
20 words
A method according to claim 1, wherein x and y are defined as being above line A of FIG. 3.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1993-03-05 | 1993-09-04 | 1994-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-05 | 1997-09-04 | 1998-03-06 | $3760.00 | Window Closed / Lapsed |
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